Saturday, September 26, 2009

JEE Chemistry Final Revision Set No. 11

1. 9.75 g of a substance when dissolved in 72.0 g of water, lowered its vapour pressure by 0.5 mm at a given temperature. The vapour pressure of water at this temperature is 25.0 mm. Calculate the molecular weight of solute.

2. Blood freezes at 272.44 K and a solution of 6.0 gm of Urea in 500 gm of water freezes at 272.63 K. Calculate osmotic pressure of blood at 310 K. (Assume density of blood at 310 K to be 1 g/cc).

3. Acetic acid in benzene forms a dimer. 1.65 gm of acetic acid when dissolved in 100 gm of benzene raised bte boiling point by 0.36°C. Calculate the Van't Hoff factor.
(kb for benzene = 2.57°C/m).

4. The heat of formation of ethane is -19.46 kcal. Bond energies of C-C, C-H and H-H are 80.0, 99.0 and 104.18kcal respectively. Calculate the heat of atomisation of graphite. (Answer: 171 kcal).

5. The standard molar enthalpies of formation of cyclohexane (liquid) and benzene(liquid) at 25°C are -156 and +49 kJ/mol respectivley. The standard enthalpy of hydrogenation of cyclohexane (liquid) at 25°C is -119 kJ/mol. Use these data to estimate the magnitude of the resonance energy of benzene. (Answer: -152 kJ/mol)

Thursday, September 10, 2009

IIT JEE Chemistry Final Revision Set No. 10

1. Calculate the equilibrium constant for the reaction,
2Fe3+ + 3I- ↔ 2Fe2+ + I3-.
The standard reduction potentials in acidic condition are 0.77 and 054 V respectively for Fe3+/Fe2+ and I3-/I- couples.

2. The hardest Boron Compound is

a. BN
b. B2O3
c. B4C
d. NaBO2

3. A solution of (+)-2-chloro-2-phenylethane in toluene racemizes slow in the presence small amount of ______________ due to the formation of ___________ .

4. CuCl has a similar structure as of Zinc blend and its structure density is 3.4 g/cm³. What is the length of unit cell edge?

a. 802pm
b. 578pm
c. 662pm
d. 678pm

5. Assertion-Reason type

Statement:For each ten degree rise of temperature the specific rate constant is nearly doubled.
Reason: Engery-wise distribution of molecules in a gas is an experimental function of temperature.

IIT JEE Chemistry Final Revision Set No. 9

1. A first order reaction is 50% complete in 30 minutes at 27°C and in 10 minutes at 47°C. Calculate the reaction rate constant at 27°C and the energy of activation of the reaction in kJ/mole.

2. Assertion Reason Type

Statement : The order of reaction cannot have a fractional value.
Reason: For an elementary reaction, the partial orders are determined by the reaction stoichiometry.

3. An element crystallises in a structure having fcc unit cell of an edge 200pm. What is the density if 200g of it contains 24×1023 atoms?

a. 43.6 g
b. 44.6 g
c. 42.6 g
d. 41.6 g

4. Give the steps for converting Ethylbenzene to 2-phenylpropionic acid.

5. the standard reduction potential of the Ag+/Ag electrode at 298K is 0.799 V. Given that for AgI, Ksp = 8.7×10-17, evaluate the potential of the Ag+/Ag electrode in a saturaded solution of AgI.

Tuesday, September 8, 2009

IIT JEE Chemistry Final Revision Set 8

1. The amount of glucose obtained by the hydrolysis of one mole maltose is _____ .

2. State true or false.

The movement of the dispersed phase towards one of the electrodes of an electric field is called cataphoresis.

3. The standard reductin potential for Cu2+/Cu is 0.34V. Calculate the reduction potential at pH = 14 for the above couple.
Take Ksp of Cu(OH) as 1×10-19

4. A current of 3.7 A is passed for 6 hrs. between Ni electrodes in 0.5L of 2M solution of Ni(NO3)2. What is the molarity of solution at the end of eletrolysis.

5. State whether the following statements are true or false.

In the case of nitration of arenes

(i). All activating sustituents are ortho, para directors.
(ii) Halogen substituents ae slightly deactivating but or ortho, para-directing.
(iii) Strongly deactivating substituents are meta directors.

IIT JEE Chemistry Final Revision Set 7

1. Assertion - Reason Type

Statement:In Williamson Synthesis, ter. alkyl halides cannot be used.

Reason:The reaction becomes reversible

2. A functional isomer of 2-methyl-2-propanol is

a. n-butyl alcohol
b. 2-butanol
c. 2-methoxy propane
d. ethyl methyl ether

3. The compound A (C2H7N) on treatment with chlorofom in alkaline medium gives a compound B. Compound B on reduction gives a compound C that responds to Liebermann's nitrosamine test. A and C are respectively:

a. ethylamine and ethyl methyl amine
b. secondary amine and primary amine
c. ethylamine and propylamine
d. primary amine and secondary amine

4. The volume of N2 liberated at S.T.P. by complete reaction of 4.5×10 kg of ethylamine with HNO2 is:

5. CH3(CH2)12COOH is the moelcular formula of ---- acid.

a. Lauric acid
b. Myristic acid
c. Stearic acid
d. Oleic acid

IIT-JEE-Chemistry - Final Revision Set 6

1.Colloids and crystalloids differ in -------

a. charge on particle
b. particle nature
c. particle size
d. concentration

2. which one of the following does not form lyophilic sol?

a. gum
b. starch
c. As2S3
d. gelatin

3. The half life of a radioactive isotope is 50 minutes. Its decay constant is ___.

4. The compound H4SiO4 represents

a. silicate
b. silicic acid
c. orthosilisic acid
d. orthosilicate

5. On treatment with cold hydroiodic acid, diethyl ether gives: ________ .

IIT JEE Chemistry Final Revision Set 5

1. Give the formula of Phenacite.

2. State true or false
Bromide is a better nucleophile than iodide.

3. The weakest oxyacid of chlorine is_________

4. Complete and balance
XeF6 + NH3

5. State true or false.
B6H10 is not a borane

IIT JEE Chemistry Final Revision Set No. 4

1. Assertion-Reason

Statement: When nitrobenzene is treated Br2 in presence of FeBr3 the major product formed is m-bromonitrobenzene.

Reason: Easier loss of H+ to region aromaticity from the meta position than from ortho and para position.

2. Most stable carbonium ion is:

a. p-NO2-C6H4-+CH2
b. C6H5+CH2
c. p_Cl-C6H42-+CH2
d. p-CH3O-C6H4-+CH2

3. State true or false

Toluene reacts with bromine in the presence of light to give benzyl bromine while in presence of FeBr3 it gives p-bromotoluene.

4. Give the steps to carry out the tranformation

Ethylbenzene to benzene.

5. Assertion - Reason type.
Statement: Normally benzene give electrophilic substitution reaction rather than electrophilic addition.

Reason: It has no double bonds

Monday, September 7, 2009

IIT JEE Chemistry - Revision Set 3

1. Potential difference of the electrical double layer formed in a colloidal sol is called
(a) Zeta potential (b) Nernst potential (c) EMF (d) Brownian potential

2. The nucleidic ratio, 13H to 11H in a sample of water is 8.0×10-8 : 1. Tritium undergoes decay with a half life period of 12.3 years. How many tritium atoms would 10.0 g of such a sample contain 40 years after the original sample is collected.

3. 1 gm of charcoal adsorbs 100 ml 0.5 M CH3COOH to form a monolayer, and thereby the molarity of CH3COOH reduces to 0.49. Calculate the surface area of the charcoal adsorbed by each molecule of acetic acid. Surface area of charcoal = 3.01×10² m²/gm

4.Hydrogen bonding is maximum in

(a) ethanol (b) Diethylether (c) Ethyl chloride (d)Triethylamine

5. The critical temperature of water is higher than that of O2 because the H2O molecule has
(a) few electrons than O2
(b) two covalent bonds
(c) dipole moment